Patients with breast cancer younger than 40 generally present with a characteristic profile—later-stage disease and more aggressive tumors with poorer prognosis—according to findings from a new study analyzing one of the largest patient data sets compiled to investigate age-related breast cancer differences, particularly for HER2 status. The research conducted by Krupa et al, which also found that these patients receive more aggressive therapies compared to older patients, was included as part of the American Society of Breast Surgeons (ASBrS) 2020 Scientific Session (Abstract 787537).

Investigators concluded that younger patients should be viewed as a unique breast cancer population with many common characteristics. They emphasized the importance of developing individualized treatments to meet this group’s needs.

“In today’s age of precision medicine and ever-evolving breast cancer treatments, understanding tumor biology and optimizing therapeutic interventions based on this is a reality and critical to improving outcomes,” said resident researcher Kelly Krupa, MD, of Allegheny General Hospital. “A consistent body of research finds breast cancers in younger patients share many common attributes. With its large patient sampling and comprehensive examination of tumor features, treatments, and outcomes, this study adds to the growing body of research on tumors characteristic of a younger population.”

National Cancer Database Analysis

Researchers analyzed data in the National Cancer Database from 26,262 women younger than age 40 and 28,537 women aged 40 or older. Younger patients tended to present with a higher clinical stage of cancer compared to older patients, with 37.16% vs 61.78% presenting at stage I, 45.92% vs 29.50% at stage II, 12.79% vs 6.17% at stage III, and 4.13% vs 2.55% at stage IV. Pathologic stages for these women were also significantly higher.

In the study, 44.48% of women younger than 40 and 68.95% of older patients had grade I and II tumors, while 55.52% of those younger than 40 and 31.06% of older patients had grade III and IV tumors, meaning that significantly more young women had poorly differentiated cancer cells correlating with more aggressive disease.

Of the 26,262 cases examined, 22.63% of younger women had HER2-positive disease compared to 13.41% of older women. Likewise, 19.82% of younger women had triple-negative breast cancer, compared with approximately half that in older patients.

In a comparison of therapeutic intervention, patients younger than 40 were more likely to have been treated with chemotherapy, whereas radiation therapy was more common among those aged 40 and over. Rates of surgical treatments showed no statistical difference.

“Breast cancer presents physicians and patients with a host of challenges and choices,” said Dr. Krupa. She pointed out that these patients also are at a very different point in their lives than older patients. For example, some therapies may come with difficult side effects that younger women will have to manage for years to come. Patients in this age group may have pregnancy-related issues, or they may be concerned about family planning after treatment. They may be more focused than older patients on the implications of their disease for siblings and young relatives.

Dr. Krupa also noted that typically women younger than 40 do not undergo screening mammography, which may account in part for their later stage at presentation. Given this and the more aggressive nature of their disease, the researchers recommended that young women with a family history of breast cancer or other risk factors should talk to their doctors about cancer risk assessment. Risk-assessment profiles may suggest a need for earlier breast cancer screening. This, in turn, can potentially lead to earlier disease diagnosis, as well as more precise therapies and better outcomes.

“The more data available about the nature of a woman’s breast cancer and the impact of specific treatment of their tumor type, the better a physician’s clinical decision-making and the more [patients can be empowered] to make informed choices about disease management and survivorship,” concluded Dr. Krupa.